1. Field of the Invention
The present invention relates to a method of specifying a partially engaged clutch stroke position for a vehicle fitted with an automatic clutch or the like and further relates to a method of diagnosing abnormalities in determination of the partially engaged clutch stroke position.
2. Description of the Related Art
In conventional vehicles with automatic clutch, an actuator is combined with a friction clutch, allowing the clutch to engage and disengage automatically.
In the engaging process of a friction clutch by automatic control, a disengaged clutch plate is first moved towards an engine flywheel rapidly while varying a clutch stroke position until a clutch face meets a flywheel surface, and then the clutch plate has to be moved slowly transmitting power to the flywheel with slip. Finally, the clutch plate is stopped to move, and the clutch is engaged completely without slip.
Therefore, it is necessary to specify the clutch stroke position at which the clutch face meets the flywheel surface and use this position as information in order to perform the automatic control in a satisfactory manner.
In this particular specification, "partially engaged clutch stroke position" means the position at which the clutch face meets the flywheel surface to start the power transmission with slip.
However, a friction clutch is subject to wear during use, and a partially engaged clutch stroke positions changes little by little.
Further, it exerts a deleterious effect on control if sensor faults and other factors cause a partially engaged clutch stroke position to become removed from the actual partially engaged clutch position.